title: The ancient and widespread nature of the ER-mitochondria encounter structure.
abstract: Mitochondria are the result of a billion years of integrative evolution, converting a once free-living bacterium to an organelle deeply linked to diverse cellular processes. One way in which mitochondria are integrated with nonendosymbiotically derived organelles is via endoplasmic reticulum (ER)-mitochondria contact sites. The ER membrane is physically tethered to the mitochondrial outer membrane by the ER-mitochondria encounter structure (ERMES). However, to date, ERMES has only ever been found in the fungal lineage. Here, we bioinformatically demonstrate that ERMES is present in lineages outside Fungi and validate this inference by mass spectrometric identification of ERMES components in Acanthamoeba castellanii mitochondria. We further demonstrate that ERMES is retained in hydrogenosome-bearing but not mitosome-bearing organisms, yielding insight into the process of reductive mitochondrial evolution. Finally, we find that the taxonomic distribution of ERMES is most consistent with rooting the eukaryotic tree between Amorphea (Animals + Fungi + Amoebozoa) + Excavata and all other eukaryotes (Diaphoratickes).
authors.affiliation: Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada. jeremy.wideman@ualberta.ca
authors.forename: Jeremy G
authors.initials: JG
authors.lastname: Wideman
authors.forename: Ryan M R
authors.initials: RM
authors.lastname: Gawryluk
authors.forename: Michael W
authors.initials: MW
authors.lastname: Gray
authors.forename: Joel B
authors.initials: JB
authors.lastname: Dacks
mesh_terms: D048248:Acanthamoeba castellanii / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*; D000818:Animals; D005075:Biological Evolution; D019295:Computational Biology; D004721:Endoplasmic Reticulum / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D007425:Intracellular Membranes / Q000737:chemistry / Q000145:classification* / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism; D010802:Phylogeny; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: C089419:MDM10 protein, S cerevisiae; C089418:MMM1 protein, S cerevisiae; C489433:MMM2 protein, S cerevisiae; C543343:Mdm12 protein, S cerevisiae; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D029701:Saccharomyces cerevisiae Proteins
keywords: ER-mitochondria contacts; ERMES complex; hydrogenosomes and mitosomes; organelle evolution